Efficient and tolerant resonant grating coupler for multimode optical interconnections

More than 60% overall coupling efficiency is achieved in the demonstrator of an optical interconnect comprising an input grating coupler, a multimode slab waveguide section and an output grating coupler. The grating coupling strength is enhanced by means of a leaky mode resonance. The efficiency of the resonant grating coupler compares favourably with the performancs reported on mirror inserts.